A local bird population will remain faithful to a particular area if a ready source of water and food is available. Consequently, bird baths are popular for attracting birds to residential homes, for example, and they may promote an interest in, and the well being of wild birds.
U.S. Pat. No. 5,784,998 discloses a bird bath having a base supporting a bird bath basin. The base includes a water chamber that extends upwardly through the center of the basin. Openings extend between the chamber and the basin to allow gravity flow of water from the chamber and into the basin. Regulating the water level in the chamber controls water level in the basin. To this end, the chamber includes a float-operated valve for controlling the supply of water from a remote source and into the chamber. The float rises and falls depending on the level of water in the chamber. The float is attached to the valve such that the valve is closed when the water reaches a predetermined maximum level within the chamber and is opened when the water level in the chamber falls below a predetermined chamber to refill the chamber to the desired level. As water in the basin is depleted, e.g. by use or evaporation, the float moves downward, thereby opening the valve and restoring the water level in the chamber and in the basin. A similar design is disclosed in U.S. Pat. No. 5,743,312.
Both of these bird bath designs suffer from several drawbacks. First, because there is no continuous flow of water into the basin, the water will freeze easily in cold weather. In order to prevent freezing in cold whether, such designs would require some type of mechanism for heating the water. In this respect, the ""998 patent discloses a heater positioned within the chamber. However, because the water does not continuously circulate between the chamber and the basin, the ability of this heater to effectively prevent freezing of water in the basin is limited, particularly in extremely cold weather.
As a result, many bird baths rely on heaters that directly heat the water in the basin. Such heating mechanisms typically take one of two forms. First, they can be in the form of an immersion heater which is placed directly in the basin during cold weather. Electricity is delivered to the heater by a power cord, which is draped over the edge of the basin and connected to a remote source of electricity. Besides being unsightly, such heaters must be installed and removed on a seasonal basis.
Alternatively, bird baths have heaters embedded in the wall of the basin or disposed within a double walled basin, as is shown in U.S. Pat. No. 4,640,226. Such designs are undesirable from a manufacturing standpoint because they limit the materials that can be used to construct the basin. In particular, the designs of the ""226 patent will work with plastic, for example, but they are not feasible when using materials such as concrete.
Additionally, the bird baths disclosed in the ""998, ""312 and ""226 patents remain full all of the time. This is undesirable because birds typically only use the bath during the day. However, at night a full bird bath tends to attract nuisance undesirable animals such as raccoons and possums. In addition, the constantly full water basin serves as a breeding ground form mosquitoes and other insects.
U.S. Pat. No. 6,079,951 describes a bird bath having a water reservoir, a bird bath basin, a water control valve for admitting fresh water into the reservoir and an air lift pump for pumping water from the reservoir to the bird bath basin. The design of the ""951 patent suffers from several drawbacks. First, it requires a remote air compressor for delivering air to the air lift pump. The tubing which extends between the air compressor and the pump must be arranged to form a loop above the highest water level in the reservoir to protect against siphoning. As a result, it is not feasible to mount the air compressor within the bird bath. Additionally, the ""951 patent does not provide for heating the water in the bath, or for draining the bath basin at night.
According to certain aspects of an embodiment of the present invention, a bird bath includes a basin adapted to hold water, a water reservoir adapted to hold water, an electric pump adapted to continuously pump water from the reservoir to the basin, and an overflow means for channeling overflow water from the basin and into the reservoir. The basin may be constructed for mounting on a base or another structure, such as a deck, fence, post or building. When a base is provided, it may be constructed to house the water reservoir and the pump. The pump and reservoir may be part of a unitary structure sized for insertion into the base. When no base is provided, the unitary pump/reservoir structure can be placed on a surface, such as the ground, or can be secured to another structure, e.g., by a mounting bracket.
The overflow means may include a water inlet positioned in the basin at the desired maximum water level and a water channel extending between the water inlet and the reservoir. The bird bath may include means for refilling the reservoir with water from a remote source so as to maintain a predetermined amount of water in the reservoir.
According to one embodiment the bird bath includes a means selectively operating the pump and means for draining the basin into the reservoir when the pump is not operating. The means for selectively delivering electricity to the pump may include a switch, a timer, or a photocell, for example. The means for draining may include a drain extending between the lowest portion of the basin and the reservoir. The drain is adapted to drain water from the basin and into the reservoir when the pump is not operating. In this respect, the pump may include an outlet in fluid communication with a flow opening positioned the base, and preferably in the lowest part of the base. When the pump is operating it pumps water from the reservoir, through the flow opening, and into the basin. When the pump is not operating, water in the basin drains under gravity flow through the flow opening, through the pump and into the reservoir.